Various forms of portable audio devices are capable of outputting an audio source. Earphones/earbuds are a common type of audio device and various forms of these devices are available and have been developed to offer different performance levels. For example, some earphone devices have an acoustic performance range based on set dimensions of front and back volumes (e.g., quantity of a three-dimensional space enclosed by some type of boundary). Typically, the pre-configured dimensions of these volumes can control how acoustics may be perceived by an end user using the earphone device. However, depending on the type of music being played, many users may desire different acoustic levels.